The Blues are out to make it 27 League One games unbeaten, but face an opponent who’ve won 10 of their last 11 visits to Fratton Park.
It appears something has to give with John Mousinho having injury and selection issues to contend with going into the game.
This is how we think he’ll go as he welcomes former Pompey boss Michael Appleton’s side to PO4.
1. GK: Will Norris
Found himself under the microscope for Chesterfield's goal last weekend. Debateable whether he should have stayed or come for the cross, but has always shown himself to be pro-active rather than reactive - and also has plenty of credit in the bank. Photo: Jason Brown
2. RB: Joe Rafferty
Arguably a tighter call than ever with Zak Swanson, after the former Arsenal man once again excelled against Leyton Orient on Tuesday night. The fact Swanson played that game does point to Rafferty starting this one, however. Photo: Jason Brown
3. CB: Sean Raggett
The red card against Leyton Orient means a competition specific suspension for Raggett - and the defender is available for Charlton. With Regan Poole out, Mousinho could shift Conor Shaughnessy over and play Ryley Towler - but a straight swap seems more likely. Photo: Jason Brown
4. CB: Conor Shaughnessy
Along with Joe Morrell, has to be the player performing at the highest level at present. The fact there's an argument to say his form has surpassed even Regan Poole's displays says it all. Photo: Jason Brown